1. Field of the Invention
The present invention relates to a light guide guiding light emitted from a light source, and more particularly, to an improved light guide, a display device and an image forming apparatus employing the same.
2. Description of the Related Art
Various electronic products have display devices for informing users of the product's operating state. These display devices are often found on image forming apparatuses, such as, e.g., printers, copying machines, fax machines, and multi-function machines, or the like.
Generally, a display device includes a light source and a light guide. When the function or operation of the electronic product changes, power is supplied to the light source or the amount or color of light emitted from the light source is changed. The light guide transmits light from the light source to the external display through a light emission surface, thereby communicating the change of the state of the instrument to a user.
In order to allow the user to easily recognize the light of the display device, light guided by the light guide should be distributed uniformly on the light emission surface of the light guide. When light is concentrated upon a specific region of the light emission surface of the light guide, the viewing angle at which the user perceives the light may be narrowed, and the amount of light incident upon a user's visual field is not uniform.
Prior attempt to improve uniformity includes scattering of diffusion material throughout the entire area of the light guide so as to disperse light within the light guide. While such a method may achieves a uniform distribution of light on the light emission surface of the light guide, it unfortunately may result in a substantial loss of light during diffusion of light, and thus greatly reduces the amount of light reaching the light emission surface of the light guide. To compensate for the loss of light, additional light sources may be employed, resulting in an increase of material costs and the power consumption of the display device.